Trona Pinnacles
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Trona Pinnacles clear sky chart from 2005-11-05 to 2018-01-20.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.
Observation TypeMinimum conditions for hour to be usableOut of hours
Clear of CloudsTransparencySeeingSky Brightness
Planetary:50%(no limit)Average(no limit)Nighttime Hours
Deep Sky:70%Average(no limit)5.9Nighttime Hours
CCD Imaging:70%Below AveragePoor(no limit)Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

PlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
Night
72%
16153
38%
48371
31%
16114
79%
16114
62%
20876

By Month

MonthDays of MonthPlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
January1st to 15thNight
71%
776
29%
2716
30%
776
77%
776
47%
1219
January16th to endNight
64%
788
37%
2466
31%
788
73%
788
49%
1177
February1st to 15thNight
66%
697
35%
2103
32%
696
74%
696
52%
1005
February16th to endNight
62%
632
36%
1895
33%
632
72%
632
50%
904
March1st to 15thNight
65%
720
33%
2160
28%
720
76%
720
58%
953
March16th to endNight
59%
768
38%
2025
23%
768
71%
768
62%
957
April1st to 15thNight
57%
719
37%
1799
17%
719
67%
719
58%
900
April16th to endNight
62%
720
40%
1800
19%
720
71%
720
68%
836
May1st to 15thNight
63%
548
40%
1628
26%
548
69%
548
73%
630
May16th to endNight
61%
562
37%
1685
25%
561
68%
561
71%
651
June1st to 15thNight
68%
447
37%
1527
32%
447
76%
447
74%
524
June16th to endNight
81%
360
42%
1440
44%
360
91%
360
86%
401
July1st to 15thNight
89%
340
35%
1360
41%
340
92%
340
65%
458
July16th to endNight
83%
519
37%
1548
32%
486
85%
486
63%
644
August1st to 15thNight
83%
717
38%
1790
23%
713
85%
713
82%
787
August16th to endNight
85%
764
45%
1910
29%
764
86%
764
80%
863
September1st to 15thNight
83%
720
42%
1848
29%
720
87%
720
74%
841
September16th to endNight
84%
716
50%
1980
42%
716
91%
716
85%
773
October1st to 15thNight
77%
720
42%
1980
35%
720
85%
720
69%
878
October16th to endNight
78%
768
46%
2376
44%
768
87%
768
69%
944
November1st to 15thNight
79%
760
37%
2470
38%
760
86%
760
63%
1002
November16th to endNight
77%
780
41%
2535
42%
780
83%
780
61%
1033
December1st to 15thNight
70%
780
35%
2535
32%
780
77%
780
51%
1136
December16th to endNight
64%
832
35%
2795
31%
832
73%
832
43%
1360

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

Occurrence of each ForecastData
Points
Cloud CoverDay
111112235%76%
49140
Night
111212235%76%
48565
TransparencyDay
11%25%15%26%37%
48824
Night
11%26%17%28%33%
48381
SeeingDay
49%21%29%25%10%
6183
Night
25%17%39%32%3
16166

By Month

Percentage Cloud Cover SW (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
42221336%10%62%
1552
16th to endDay
5%213213346%61%
1854
February1st to 15thDay
21221345%8%67%
1751
16th to endDay
4222213447%64%
1579
March1st to 15thDay
1211112448%69%
1800
16th to endDay
11111235%9%70%
2196
April1st to 15thDay
1112212236%73%
2149
16th to endDay
11111236%80%
2160
May1st to 15thDay
111235%83%
2320
16th to endDay
11111112481%
2429
June1st to 15thDay
1111485%
2429
16th to endDay
11111189%
2520
July1st to 15thDay
11121223477%
2520
16th to endDay
212212346%73%
2509
August1st to 15thDay
111112384%
2160
16th to endDay
11122484%
2292
September1st to 15thDay
1111122482%
2111
16th to endDay
111389%
1980
October1st to 15thDay
112112225%78%
1980
16th to endDay
111111235%78%
1846
November1st to 15thDay
111112236%76%
1719
16th to endDay
11212347%72%
1755
December1st to 15thDay
111332335%8%64%
1755
16th to endDay
3323313448%61%
1774
January1st to 15thNight
1213223347%67%
2716
16th to endNight
3213312246%67%
2466
February1st to 15thNight
1212312337%67%
2101
16th to endNight
4211213347%67%
1895
March1st to 15thNight
131235%7%71%
2160
16th to endNight
1111235%7%73%
2025
April1st to 15thNight
111212226%75%
1799
16th to endNight
11211135%81%
1800
May1st to 15thNight
2145%82%
1628
16th to endNight
1112484%
1684
June1st to 15thNight
1135%85%
1527
16th to endNight
111291%
1440
July1st to 15thNight
11211222479%
1440
16th to endNight
1121334475%
1655
August1st to 15thNight
11222483%
1800
16th to endNight
11121384%
1910
September1st to 15thNight
121122481%
1848
16th to endNight
112389%
1980
October1st to 15thNight
111123480%
1980
16th to endNight
1111112482%
2376
November1st to 15thNight
11112335%77%
2470
16th to endNight
111112237%75%
2535
December1st to 15thNight
2112213237%69%
2535
16th to endNight
4212314346%64%
2795

Transparency (when cloud cover <= 30%)
Color Meanings:
Too cloudy to forecast Poor Below Average Average Above average Transparent
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
18%411%27%28%10%
1552
16th to endDay
23%49%24%24%14%
1854
February1st to 15thDay
14%48%23%29%18%
1751
16th to endDay
20%5%7%22%29%13%
1579
March1st to 15thDay
12%39%24%29%20%
1800
16th to endDay
11%49%22%30%20%
2196
April1st to 15thDay
14%35%19%33%22%
2149
16th to endDay
8%17%18%32%30%
2160
May1st to 15thDay
6%25%16%32%37%
2320
16th to endDay
10%1313%35%34%
2432
June1st to 15thDay
6%1210%23%55%
2429
16th to endDay
5%11312%75%
2520
July1st to 15thDay
10%246%14%61%
2371
16th to endDay
13%3410%20%48%
2353
August1st to 15thDay
7%127%16%65%
2146
16th to endDay
6%225%24%59%
2292
September1st to 15thDay
8%237%20%58%
2111
16th to endDay
4117%32%53%
1980
October1st to 15thDay
10%3311%32%38%
1980
16th to endDay
10%2412%29%40%
1846
November1st to 15thDay
10%27%21%38%20%
1719
16th to endDay
12%38%20%33%21%
1755
December1st to 15thDay
18%411%23%28%14%
1755
16th to endDay
22%5%10%24%24%12%
1774
January1st to 15thNight
18%48%25%29%12%
2716
16th to endNight
19%38%22%25%19%
2466
February1st to 15thNight
18%39%20%26%22%
2112
16th to endNight
17%47%24%31%14%
1895
March1st to 15thNight
12%39%21%30%21%
2160
16th to endNight
11%39%27%31%17%
2025
April1st to 15thNight
13%35%23%34%19%
1799
16th to endNight
8%25%23%37%23%
1800
May1st to 15thNight
5%2320%34%32%
1629
16th to endNight
6%16%17%37%30%
1685
June1st to 15thNight
5%2312%25%51%
1527
16th to endNight
316%13%73%
1440
July1st to 15thNight
9%137%13%64%
1360
16th to endNight
11%35%8%22%48%
1548
August1st to 15thNight
5%137%20%60%
1790
16th to endNight
7%125%27%56%
1910
September1st to 15thNight
9%136%25%52%
1848
16th to endNight
3127%29%55%
1980
October1st to 15thNight
9%3311%33%39%
1980
16th to endNight
8%2312%28%44%
2376
November1st to 15thNight
11%2419%37%24%
2470
16th to endNight
11%36%19%29%29%
2535
December1st to 15thNight
16%310%19%30%18%
2535
16th to endNight
21%5%9%23%26%13%
2795

Seeing (when cloud cover <= 80%)
Color Meanings:
Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
14%11%13%28%26%5%
90
16th to endDay
11%10%17%26%20%12%
239
February1st to 15thDay
6%10%17%33%22%9%
266
16th to endDay
11%18%17%25%21%5%
238
March1st to 15thDay
6%14%22%23%22%9%
270
16th to endDay
5%14%27%27%19%5%
288
April1st to 15thDay
11%19%22%23%19%3
269
16th to endDay
420%30%28%12%3
270
May1st to 15thDay
213%35%25%18%5%
288
16th to endDay
313%27%25%20%9%
330
June1st to 15thDay
39%29%26%21%8%
315
16th to endDay
5%27%23%27%15%
315
July1st to 15thDay
2222%30%26%15%
305
16th to endDay
3216%34%29%13%
327
August1st to 15thDay
2421%38%22%11%
315
16th to endDay
1215%33%28%18%
332
September1st to 15thDay
2320%32%31%8%
315
16th to endDay
2414%31%33%12%
315
October1st to 15thDay
37%20%37%24%6%
315
16th to endDay
37%12%18%36%21%
255
November1st to 15thDay
2213%27%36%17%
135
16th to endDay
28%12%33%35%7%
135
December1st to 15thDay
211%44%29%10%
135
16th to endDay
8%319%30%28%9%
121
January1st to 15thNight
3315%42%31%4
780
16th to endNight
5%321%38%28%2
788
February1st to 15thNight
25%19%43%26%3
704
16th to endNight
6%8%20%41%21%2
632
March1st to 15thNight
17%20%43%22%3
720
16th to endNight
29%26%33%25%1
768
April1st to 15thNight
312%24%35%21%1
719
16th to endNight
110%23%36%24%3
720
May1st to 15thNight
7%27%40%21%2
549
16th to endNight
110%25%36%25%
563
June1st to 15thNight
6%23%42%25%1
447
16th to endNight
116%46%33%1
360
July1st to 15thNight
1449%41%1
340
16th to endNight
10%43%41%2
519
August1st to 15thNight
113%39%41%4
717
16th to endNight
110%32%45%9%
764
September1st to 15thNight
19%33%47%6%
720
16th to endNight
211%33%47%5%
716
October1st to 15thNight
414%43%33%3
720
16th to endNight
1412%32%41%7%
768
November1st to 15thNight
1313%39%37%4
760
16th to endNight
25%11%37%38%4
780
December1st to 15thNight
46%14%42%29%2
780
16th to endNight
5%420%40%25%3
832
Page generated at 2018-01-21 09:19:30. Version ac04

Copyright 2018 A. Danko


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